The need is increasingly more felt to monitor and reduce atmospheric pollution which, as is known, is the cause of numerous and by now widespread illnesses affecting mankind such as, for example, cardio-circulatory lung diseases and immune system illnesses.
To monitor atmospheric pollution, in particular, the use is known of special detection units, suitably located inside a geographic area to be monitored and having atmospheric sensors able to detect gases and polluting substances such as, e.g., carbon monoxide (CO), nitrogen oxides (NOx), sulphur oxides (SOx), hydrocarbons (CxHy), ozone (O3) and particulate (PTS).
Nevertheless, such units are fixed installations and, consequently, they permit detecting atmospheric pollution values only in correspondence to precise sites inside the geographic area to be monitored, while the atmospheric pollution in correspondence to other areas must necessarily be determined by approximation.
The use is also known of mobile laboratories having several atmospheric sensors and the equipment needed to process and analyze data.
Nevertheless, the use of such mobile laboratories is very expensive, inasmuch as it requires the use of complex equipment and the continuous on-board presence of qualified personnel.
Furthermore, by means of the use of mobile laboratories, an in any case small number of detection operations can be performed, and with checks repeated inside the same area greatly dilated in time.
To overcome the above drawbacks affecting known solutions, electronic appliances are used installable on vehicles, having one or more atmospheric sensors and suitable communication devices, able to send the collected pollution data to one or more remote processing units.
In particular, the document EP 1 113 268 A1 describes a method and an appliance for monitoring the quality of air inside a predetermined geographic area, wherein the appliance comprises a fixed station and at least a mobile station installed on a vehicle.
The mobile station has atmospheric sensors for detecting polluting gases, a satellite receiver to determine the position of the vehicle over time, an acquisition unit which receives data from the atmospheric sensors and from the satellite receiver and a transmission interface able to transmit the collected data.
The fixed station, furthermore, comprises a processor with communication device of the modem type with antenna and a software program for the display and analysis of the data collected by and received from the mobile station.
Such known method and appliance propose to provide a continuous control of the pollution conditions inside the monitored area by means of a representation of average concentrations (hourly, daily, monthly, etc.) of the polluting substances present.
Furthermore, the document WO 2011/069136 A2 describes an electric wheel for bicycles which can be provided with at least an environmental sensor, a satellite receiver for determining the position of the bicycle over time, and a communication unit for transmitting the detected data relating to the environmental pollution and to the position.
However, the appliances of known type are not free from drawbacks.
In fact, commonly used environmental sensors require continuous maintenance jobs that have to be repeated over time and which aim at setting and calibrating the metrological characteristics defining the precision of the sensors themselves, such as e.g., accuracy, resolution, zero drift and span drift.
In particular, the precision of an environmental sensor is the degree of approximation with which the sensor is able to define the measured quantity, accuracy is the capacity of the sensor to detect a concentration value of a gas more or less close to the real concentration value, while resolution is the smallest quantity the sensor is able to detect.
Furthermore, fundamental parameters in assessing the efficacy of an environmental sensor are the zero drift, which indicates the gradual variance in time of the average response to a zero-setting gas, i.e., to a gas that should be detected as zero by the sensor, and the span drift, which instead indicates the gradual variance in time of the average response to a gas of known concentration.
These parameters can vary over time and this inevitably ends up negatively affecting the quality of the measurements taken by the atmospheric sensor.
The periodical intervention of skilled technicians is therefore required to make calibrations and this operation often requires the de-installation of the sensor and its dispatch to laboratories able to perform all the fine-tuning operations. Inevitably, this involves high maintenance costs, as well as periods of inactivity of the atmospheric sensors which are not at all negligible and are repeated over time.